General Motors' plug-in electric Chevrolet Volt will get "thousands" cheaper when the time comes for its next generation, a top GM executive says.

Instead of shoehorning the electric powerplant into a conventional GM compact-car platform, the next Volt will be purpose-built. That will allow the ability to better package the batteries and other specialized components, says Mark Reuss, president of GM North America. He spoke Wednesday night at Automotive News' World Congress here in Detroit.

"The next generation will be even better," he vowed. And, if it is purpose-built, there are "thousands of dollars that can come out of it."

GM managed to triple sales of the Volt last year despite its steep price -- at least for a Chevy compact -- of $39,995. Sales were helped by cheap lease deals and changes that allowed car pool lane access for solo drivers in congested California.

He pointed to surveys that showed Chevrolet Volt owners are among the most pleased of all owners of new vehicles, "happier than Porsche 911 buyers."

The Volt saves gas by allowing owners to plug them in overnight to charge the batteries overnight for 35 miles or more of pure electric driving. After that, a gas engine takes over.

At the North American International Auto Show in Detroit this week, GM introduced a plug-in stablemate to Volt, the lush Cadillac ELR.